client.c

Go to the documentation of this file.

/*
 * net/9p/clnt.c
 *
 * 9P Client
 *
 *  Copyright (C) 2008 by Eric Van Hensbergen <[email protected]>
 *  Copyright (C) 2007 by Latchesar Ionkov <[email protected]>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/idr.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <net/9p/9p.h>
#include <linux/parser.h>
#include <net/9p/client.h>
#include <net/9p/transport.h>
#include "protocol.h"

#define CREATE_TRACE_POINTS
#include <trace/events/9p.h>

/*
  * Client Option Parsing (code inspired by NFS code)
  *  - a little lazy - parse all client options
  */

enum {
    Opt_msize,
    Opt_trans,
    Opt_legacy,
    Opt_version,
    Opt_err,
};

static const match_table_t tokens = {
    {Opt_msize, "msize=%u"},
    {Opt_legacy, "noextend"},
    {Opt_trans, "trans=%s"},
    {Opt_version, "version=%s"},
    {Opt_err, NULL},
};

inline int p9_is_proto_dotl(struct p9_client *clnt)
{
    return clnt->proto_version == p9_proto_2000L;
}
EXPORT_SYMBOL(p9_is_proto_dotl);

inline int p9_is_proto_dotu(struct p9_client *clnt)
{
    return clnt->proto_version == p9_proto_2000u;
}
EXPORT_SYMBOL(p9_is_proto_dotu);

/*
 * Some error codes are taken directly from the server replies,
 * make sure they are valid.
 */
static int safe_errno(int err)
{
    if ((err > 0) || (err < -MAX_ERRNO)) {
        p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
        return -EPROTO;
    }
    return err;
}


/* Interpret mount option for protocol version */
static int get_protocol_version(char *s)
{
    int version = -EINVAL;

    if (!strcmp(s, "9p2000")) {
        version = p9_proto_legacy;
        p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
    } else if (!strcmp(s, "9p2000.u")) {
        version = p9_proto_2000u;
        p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
    } else if (!strcmp(s, "9p2000.L")) {
        version = p9_proto_2000L;
        p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
    } else
        pr_info("Unknown protocol version %s\n", s);

    return version;
}

static int parse_opts(char *opts, struct p9_client *clnt)
{
    char *options, *tmp_options;
    char *p;
    substring_t args[MAX_OPT_ARGS];
    int option;
    char *s;
    int ret = 0;

    clnt->proto_version = p9_proto_2000u;
    clnt->msize = 8192;

    if (!opts)
        return 0;

    tmp_options = kstrdup(opts, GFP_KERNEL);
    if (!tmp_options) {
        p9_debug(P9_DEBUG_ERROR,
             "failed to allocate copy of option string\n");
        return -ENOMEM;
    }
    options = tmp_options;

    while ((p = strsep(&options, ",")) != NULL) {
        int token, r;
        if (!*p)
            continue;
        token = match_token(p, tokens, args);
        switch (token) {
        case Opt_msize:
            r = match_int(&args[0], &option);
            if (r < 0) {
                p9_debug(P9_DEBUG_ERROR,
                     "integer field, but no integer?\n");
                ret = r;
                continue;
            }
            clnt->msize = option;
            break;
        case Opt_trans:
            s = match_strdup(&args[0]);
            if (!s) {
                ret = -ENOMEM;
                p9_debug(P9_DEBUG_ERROR,
                     "problem allocating copy of trans arg\n");
                goto free_and_return;
             }
            clnt->trans_mod = v9fs_get_trans_by_name(s);
            if (clnt->trans_mod == NULL) {
                pr_info("Could not find request transport: %s\n",
                    s);
                ret = -EINVAL;
                kfree(s);
                goto free_and_return;
            }
            kfree(s);
            break;
        case Opt_legacy:
            clnt->proto_version = p9_proto_legacy;
            break;
        case Opt_version:
            s = match_strdup(&args[0]);
            if (!s) {
                ret = -ENOMEM;
                p9_debug(P9_DEBUG_ERROR,
                     "problem allocating copy of version arg\n");
                goto free_and_return;
            }
            ret = get_protocol_version(s);
            if (ret == -EINVAL) {
                kfree(s);
                goto free_and_return;
            }
            kfree(s);
            clnt->proto_version = ret;
            break;
        default:
            continue;
        }
    }

free_and_return:
    kfree(tmp_options);
    return ret;
}

static struct p9_req_t *
p9_tag_alloc(struct p9_client *c, u16 tag, unsigned int max_size)
{
    unsigned long flags;
    int row, col;
    struct p9_req_t *req;
    int alloc_msize = min(c->msize, max_size);

    /* This looks up the original request by tag so we know which
     * buffer to read the data into */
    tag++;

    if (tag >= c->max_tag) {
        spin_lock_irqsave(&c->lock, flags);
        /* check again since original check was outside of lock */
        while (tag >= c->max_tag) {
            row = (tag / P9_ROW_MAXTAG);
            c->reqs[row] = kcalloc(P9_ROW_MAXTAG,
                    sizeof(struct p9_req_t), GFP_ATOMIC);

            if (!c->reqs[row]) {
                pr_err("Couldn't grow tag array\n");
                spin_unlock_irqrestore(&c->lock, flags);
                return ERR_PTR(-ENOMEM);
            }
            for (col = 0; col < P9_ROW_MAXTAG; col++) {
                c->reqs[row][col].status = REQ_STATUS_IDLE;
                c->reqs[row][col].tc = NULL;
            }
            c->max_tag += P9_ROW_MAXTAG;
        }
        spin_unlock_irqrestore(&c->lock, flags);
    }
    row = tag / P9_ROW_MAXTAG;
    col = tag % P9_ROW_MAXTAG;

    req = &c->reqs[row][col];
    if (!req->tc) {
        req->wq = kmalloc(sizeof(wait_queue_head_t), GFP_NOFS);
        if (!req->wq) {
            pr_err("Couldn't grow tag array\n");
            return ERR_PTR(-ENOMEM);
        }
        init_waitqueue_head(req->wq);
        req->tc = kmalloc(sizeof(struct p9_fcall) + alloc_msize,
                  GFP_NOFS);
        req->rc = kmalloc(sizeof(struct p9_fcall) + alloc_msize,
                  GFP_NOFS);
        if ((!req->tc) || (!req->rc)) {
            pr_err("Couldn't grow tag array\n");
            kfree(req->tc);
            kfree(req->rc);
            kfree(req->wq);
            req->tc = req->rc = NULL;
            req->wq = NULL;
            return ERR_PTR(-ENOMEM);
        }
        req->tc->capacity = alloc_msize;
        req->rc->capacity = alloc_msize;
        req->tc->sdata = (char *) req->tc + sizeof(struct p9_fcall);
        req->rc->sdata = (char *) req->rc + sizeof(struct p9_fcall);
    }

    p9pdu_reset(req->tc);
    p9pdu_reset(req->rc);

    req->tc->tag = tag-1;
    req->status = REQ_STATUS_ALLOC;

    return &c->reqs[row][col];
}

struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
{
    int row, col;

    /* This looks up the original request by tag so we know which
     * buffer to read the data into */
    tag++;

    if(tag >= c->max_tag) 
        return NULL;

    row = tag / P9_ROW_MAXTAG;
    col = tag % P9_ROW_MAXTAG;

    return &c->reqs[row][col];
}
EXPORT_SYMBOL(p9_tag_lookup);

static int p9_tag_init(struct p9_client *c)
{
    int err = 0;

    c->tagpool = p9_idpool_create();
    if (IS_ERR(c->tagpool)) {
        err = PTR_ERR(c->tagpool);
        goto error;
    }
    err = p9_idpool_get(c->tagpool); /* reserve tag 0 */
    if (err < 0) {
        p9_idpool_destroy(c->tagpool);
        goto error;
    }
    c->max_tag = 0;
error:
    return err;
}

static void p9_tag_cleanup(struct p9_client *c)
{
    int row, col;

    /* check to insure all requests are idle */
    for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
        for (col = 0; col < P9_ROW_MAXTAG; col++) {
            if (c->reqs[row][col].status != REQ_STATUS_IDLE) {
                p9_debug(P9_DEBUG_MUX,
                     "Attempting to cleanup non-free tag %d,%d\n",
                     row, col);
                /* TODO: delay execution of cleanup */
                return;
            }
        }
    }

    if (c->tagpool) {
        p9_idpool_put(0, c->tagpool); /* free reserved tag 0 */
        p9_idpool_destroy(c->tagpool);
    }

    /* free requests associated with tags */
    for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
        for (col = 0; col < P9_ROW_MAXTAG; col++) {
            kfree(c->reqs[row][col].wq);
            kfree(c->reqs[row][col].tc);
            kfree(c->reqs[row][col].rc);
        }
        kfree(c->reqs[row]);
    }
    c->max_tag = 0;
}

static void p9_free_req(struct p9_client *c, struct p9_req_t *r)
{
    int tag = r->tc->tag;
    p9_debug(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);

    r->status = REQ_STATUS_IDLE;
    if (tag != P9_NOTAG && p9_idpool_check(tag, c->tagpool))
        p9_idpool_put(tag, c->tagpool);
}

void p9_client_cb(struct p9_client *c, struct p9_req_t *req)
{
    p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc->tag);
    wake_up(req->wq);
    p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
}
EXPORT_SYMBOL(p9_client_cb);

int
p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
                                int rewind)
{
    int8_t r_type;
    int16_t r_tag;
    int32_t r_size;
    int offset = pdu->offset;
    int err;

    pdu->offset = 0;
    if (pdu->size == 0)
        pdu->size = 7;

    err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
    if (err)
        goto rewind_and_exit;

    pdu->size = r_size;
    pdu->id = r_type;
    pdu->tag = r_tag;

    p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
         pdu->size, pdu->id, pdu->tag);

    if (type)
        *type = r_type;
    if (tag)
        *tag = r_tag;
    if (size)
        *size = r_size;


rewind_and_exit:
    if (rewind)
        pdu->offset = offset;
    return err;
}
EXPORT_SYMBOL(p9_parse_header);

static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
{
    int8_t type;
    int err;
    int ecode;

    err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
    /*
     * dump the response from server
     * This should be after check errors which poplulate pdu_fcall.
     */
    trace_9p_protocol_dump(c, req->rc);
    if (err) {
        p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
        return err;
    }
    if (type != P9_RERROR && type != P9_RLERROR)
        return 0;

    if (!p9_is_proto_dotl(c)) {
        char *ename;
        err = p9pdu_readf(req->rc, c->proto_version, "s?d",
                  &ename, &ecode);
        if (err)
            goto out_err;

        if (p9_is_proto_dotu(c))
            err = -ecode;

        if (!err || !IS_ERR_VALUE(err)) {
            err = p9_errstr2errno(ename, strlen(ename));

            p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
                 -ecode, ename);
        }
        kfree(ename);
    } else {
        err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
        err = -ecode;

        p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
    }

    return err;

out_err:
    p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);

    return err;
}

static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
                  char *uidata, int in_hdrlen, int kern_buf)
{
    int err;
    int ecode;
    int8_t type;
    char *ename = NULL;

    err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
    /*
     * dump the response from server
     * This should be after parse_header which poplulate pdu_fcall.
     */
    trace_9p_protocol_dump(c, req->rc);
    if (err) {
        p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
        return err;
    }

    if (type != P9_RERROR && type != P9_RLERROR)
        return 0;

    if (!p9_is_proto_dotl(c)) {
        /* Error is reported in string format */
        uint16_t len;
        /* 7 = header size for RERROR, 2 is the size of string len; */
        int inline_len = in_hdrlen - (7 + 2);

        /* Read the size of error string */
        err = p9pdu_readf(req->rc, c->proto_version, "w", &len);
        if (err)
            goto out_err;

        ename = kmalloc(len + 1, GFP_NOFS);
        if (!ename) {
            err = -ENOMEM;
            goto out_err;
        }
        if (len <= inline_len) {
            /* We have error in protocol buffer itself */
            if (pdu_read(req->rc, ename, len)) {
                err = -EFAULT;
                goto out_free;

            }
        } else {
            /*
             *  Part of the data is in user space buffer.
             */
            if (pdu_read(req->rc, ename, inline_len)) {
                err = -EFAULT;
                goto out_free;

            }
            if (kern_buf) {
                memcpy(ename + inline_len, uidata,
                       len - inline_len);
            } else {
                err = copy_from_user(ename + inline_len,
                             uidata, len - inline_len);
                if (err) {
                    err = -EFAULT;
                    goto out_free;
                }
            }
        }
        ename[len] = 0;
        if (p9_is_proto_dotu(c)) {
            /* For dotu we also have error code */
            err = p9pdu_readf(req->rc,
                      c->proto_version, "d", &ecode);
            if (err)
                goto out_free;
            err = -ecode;
        }
        if (!err || !IS_ERR_VALUE(err)) {
            err = p9_errstr2errno(ename, strlen(ename));

            p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
                 -ecode, ename);
        }
        kfree(ename);
    } else {
        err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
        err = -ecode;

        p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
    }
    return err;

out_free:
    kfree(ename);
out_err:
    p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
    return err;
}

static struct p9_req_t *
p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);

static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
{
    struct p9_req_t *req;
    int16_t oldtag;
    int err;

    err = p9_parse_header(oldreq->tc, NULL, NULL, &oldtag, 1);
    if (err)
        return err;

    p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);

    req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
    if (IS_ERR(req))
        return PTR_ERR(req);


    /* if we haven't received a response for oldreq,
       remove it from the list. */
    spin_lock(&c->lock);
    if (oldreq->status == REQ_STATUS_FLSH)
        list_del(&oldreq->req_list);
    spin_unlock(&c->lock);

    p9_free_req(c, req);
    return 0;
}

static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
                          int8_t type, int req_size,
                          const char *fmt, va_list ap)
{
    int tag, err;
    struct p9_req_t *req;

    p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);

    /* we allow for any status other than disconnected */
    if (c->status == Disconnected)
        return ERR_PTR(-EIO);

    /* if status is begin_disconnected we allow only clunk request */
    if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
        return ERR_PTR(-EIO);

    tag = P9_NOTAG;
    if (type != P9_TVERSION) {
        tag = p9_idpool_get(c->tagpool);
        if (tag < 0)
            return ERR_PTR(-ENOMEM);
    }

    req = p9_tag_alloc(c, tag, req_size);
    if (IS_ERR(req))
        return req;

    /* marshall the data */
    p9pdu_prepare(req->tc, tag, type);
    err = p9pdu_vwritef(req->tc, c->proto_version, fmt, ap);
    if (err)
        goto reterr;
    p9pdu_finalize(c, req->tc);
    trace_9p_client_req(c, type, tag);
    return req;
reterr:
    p9_free_req(c, req);
    return ERR_PTR(err);
}

static struct p9_req_t *
p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
{
    va_list ap;
    int sigpending, err;
    unsigned long flags;
    struct p9_req_t *req;

    va_start(ap, fmt);
    req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
    va_end(ap);
    if (IS_ERR(req))
        return req;

    if (signal_pending(current)) {
        sigpending = 1;
        clear_thread_flag(TIF_SIGPENDING);
    } else
        sigpending = 0;

    err = c->trans_mod->request(c, req);
    if (err < 0) {
        if (err != -ERESTARTSYS && err != -EFAULT)
            c->status = Disconnected;
        goto reterr;
    }
again:
    /* Wait for the response */
    err = wait_event_interruptible(*req->wq,
                       req->status >= REQ_STATUS_RCVD);

    if ((err == -ERESTARTSYS) && (c->status == Connected)
                  && (type == P9_TFLUSH)) {
        sigpending = 1;
        clear_thread_flag(TIF_SIGPENDING);
        goto again;
    }

    if (req->status == REQ_STATUS_ERROR) {
        p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
        err = req->t_err;
    }
    if ((err == -ERESTARTSYS) && (c->status == Connected)) {
        p9_debug(P9_DEBUG_MUX, "flushing\n");
        sigpending = 1;
        clear_thread_flag(TIF_SIGPENDING);

        if (c->trans_mod->cancel(c, req))
            p9_client_flush(c, req);

        /* if we received the response anyway, don't signal error */
        if (req->status == REQ_STATUS_RCVD)
            err = 0;
    }
    if (sigpending) {
        spin_lock_irqsave(&current->sighand->siglock, flags);
        recalc_sigpending();
        spin_unlock_irqrestore(&current->sighand->siglock, flags);
    }
    if (err < 0)
        goto reterr;

    err = p9_check_errors(c, req);
    trace_9p_client_res(c, type, req->rc->tag, err);
    if (!err)
        return req;
reterr:
    p9_free_req(c, req);
    return ERR_PTR(safe_errno(err));
}

static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
                     char *uidata, char *uodata,
                     int inlen, int olen, int in_hdrlen,
                     int kern_buf, const char *fmt, ...)
{
    va_list ap;
    int sigpending, err;
    unsigned long flags;
    struct p9_req_t *req;

    va_start(ap, fmt);
    /*
     * We allocate a inline protocol data of only 4k bytes.
     * The actual content is passed in zero-copy fashion.
     */
    req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
    va_end(ap);
    if (IS_ERR(req))
        return req;

    if (signal_pending(current)) {
        sigpending = 1;
        clear_thread_flag(TIF_SIGPENDING);
    } else
        sigpending = 0;

    /* If we are called with KERNEL_DS force kern_buf */
    if (segment_eq(get_fs(), KERNEL_DS))
        kern_buf = 1;

    err = c->trans_mod->zc_request(c, req, uidata, uodata,
                       inlen, olen, in_hdrlen, kern_buf);
    if (err < 0) {
        if (err == -EIO)
            c->status = Disconnected;
        goto reterr;
    }
    if (req->status == REQ_STATUS_ERROR) {
        p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
        err = req->t_err;
    }
    if ((err == -ERESTARTSYS) && (c->status == Connected)) {
        p9_debug(P9_DEBUG_MUX, "flushing\n");
        sigpending = 1;
        clear_thread_flag(TIF_SIGPENDING);

        if (c->trans_mod->cancel(c, req))
            p9_client_flush(c, req);

        /* if we received the response anyway, don't signal error */
        if (req->status == REQ_STATUS_RCVD)
            err = 0;
    }
    if (sigpending) {
        spin_lock_irqsave(&current->sighand->siglock, flags);
        recalc_sigpending();
        spin_unlock_irqrestore(&current->sighand->siglock, flags);
    }
    if (err < 0)
        goto reterr;

    err = p9_check_zc_errors(c, req, uidata, in_hdrlen, kern_buf);
    trace_9p_client_res(c, type, req->rc->tag, err);
    if (!err)
        return req;
reterr:
    p9_free_req(c, req);
    return ERR_PTR(safe_errno(err));
}

static struct p9_fid *p9_fid_create(struct p9_client *clnt)
{
    int ret;
    struct p9_fid *fid;
    unsigned long flags;

    p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
    fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
    if (!fid)
        return ERR_PTR(-ENOMEM);

    ret = p9_idpool_get(clnt->fidpool);
    if (ret < 0) {
        ret = -ENOSPC;
        goto error;
    }
    fid->fid = ret;

    memset(&fid->qid, 0, sizeof(struct p9_qid));
    fid->mode = -1;
    fid->uid = current_fsuid();
    fid->clnt = clnt;
    fid->rdir = NULL;
    spin_lock_irqsave(&clnt->lock, flags);
    list_add(&fid->flist, &clnt->fidlist);
    spin_unlock_irqrestore(&clnt->lock, flags);

    return fid;

error:
    kfree(fid);
    return ERR_PTR(ret);
}

static void p9_fid_destroy(struct p9_fid *fid)
{
    struct p9_client *clnt;
    unsigned long flags;

    p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
    clnt = fid->clnt;
    p9_idpool_put(fid->fid, clnt->fidpool);
    spin_lock_irqsave(&clnt->lock, flags);
    list_del(&fid->flist);
    spin_unlock_irqrestore(&clnt->lock, flags);
    kfree(fid->rdir);
    kfree(fid);
}

static int p9_client_version(struct p9_client *c)
{
    int err = 0;
    struct p9_req_t *req;
    char *version;
    int msize;

    p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
         c->msize, c->proto_version);

    switch (c->proto_version) {
    case p9_proto_2000L:
        req = p9_client_rpc(c, P9_TVERSION, "ds",
                    c->msize, "9P2000.L");
        break;
    case p9_proto_2000u:
        req = p9_client_rpc(c, P9_TVERSION, "ds",
                    c->msize, "9P2000.u");
        break;
    case p9_proto_legacy:
        req = p9_client_rpc(c, P9_TVERSION, "ds",
                    c->msize, "9P2000");
        break;
    default:
        return -EINVAL;
        break;
    }

    if (IS_ERR(req))
        return PTR_ERR(req);

    err = p9pdu_readf(req->rc, c->proto_version, "ds", &msize, &version);
    if (err) {
        p9_debug(P9_DEBUG_9P, "version error %d\n", err);
        trace_9p_protocol_dump(c, req->rc);
        goto error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
    if (!strncmp(version, "9P2000.L", 8))
        c->proto_version = p9_proto_2000L;
    else if (!strncmp(version, "9P2000.u", 8))
        c->proto_version = p9_proto_2000u;
    else if (!strncmp(version, "9P2000", 6))
        c->proto_version = p9_proto_legacy;
    else {
        err = -EREMOTEIO;
        goto error;
    }

    if (msize < c->msize)
        c->msize = msize;

error:
    kfree(version);
    p9_free_req(c, req);

    return err;
}

struct p9_client *p9_client_create(const char *dev_name, char *options)
{
    int err;
    struct p9_client *clnt;

    err = 0;
    clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
    if (!clnt)
        return ERR_PTR(-ENOMEM);

    clnt->trans_mod = NULL;
    clnt->trans = NULL;
    spin_lock_init(&clnt->lock);
    INIT_LIST_HEAD(&clnt->fidlist);

    err = p9_tag_init(clnt);
    if (err < 0)
        goto free_client;

    err = parse_opts(options, clnt);
    if (err < 0)
        goto destroy_tagpool;

    if (!clnt->trans_mod)
        clnt->trans_mod = v9fs_get_default_trans();

    if (clnt->trans_mod == NULL) {
        err = -EPROTONOSUPPORT;
        p9_debug(P9_DEBUG_ERROR,
             "No transport defined or default transport\n");
        goto destroy_tagpool;
    }

    clnt->fidpool = p9_idpool_create();
    if (IS_ERR(clnt->fidpool)) {
        err = PTR_ERR(clnt->fidpool);
        goto put_trans;
    }

    p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
         clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);

    err = clnt->trans_mod->create(clnt, dev_name, options);
    if (err)
        goto destroy_fidpool;

    if (clnt->msize > clnt->trans_mod->maxsize)
        clnt->msize = clnt->trans_mod->maxsize;

    err = p9_client_version(clnt);
    if (err)
        goto close_trans;

    return clnt;

close_trans:
    clnt->trans_mod->close(clnt);
destroy_fidpool:
    p9_idpool_destroy(clnt->fidpool);
put_trans:
    v9fs_put_trans(clnt->trans_mod);
destroy_tagpool:
    p9_idpool_destroy(clnt->tagpool);
free_client:
    kfree(clnt);
    return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_create);

void p9_client_destroy(struct p9_client *clnt)
{
    struct p9_fid *fid, *fidptr;

    p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);

    if (clnt->trans_mod)
        clnt->trans_mod->close(clnt);

    v9fs_put_trans(clnt->trans_mod);

    list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist) {
        pr_info("Found fid %d not clunked\n", fid->fid);
        p9_fid_destroy(fid);
    }

    if (clnt->fidpool)
        p9_idpool_destroy(clnt->fidpool);

    p9_tag_cleanup(clnt);

    kfree(clnt);
}
EXPORT_SYMBOL(p9_client_destroy);

void p9_client_disconnect(struct p9_client *clnt)
{
    p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
    clnt->status = Disconnected;
}
EXPORT_SYMBOL(p9_client_disconnect);

void p9_client_begin_disconnect(struct p9_client *clnt)
{
    p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
    clnt->status = BeginDisconnect;
}
EXPORT_SYMBOL(p9_client_begin_disconnect);

struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
    char *uname, u32 n_uname, char *aname)
{
    int err = 0;
    struct p9_req_t *req;
    struct p9_fid *fid;
    struct p9_qid qid;


    p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
         afid ? afid->fid : -1, uname, aname);
    fid = p9_fid_create(clnt);
    if (IS_ERR(fid)) {
        err = PTR_ERR(fid);
        fid = NULL;
        goto error;
    }

    req = p9_client_rpc(clnt, P9_TATTACH, "ddss?d", fid->fid,
            afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    err = p9pdu_readf(req->rc, clnt->proto_version, "Q", &qid);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        p9_free_req(clnt, req);
        goto error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
         qid.type, (unsigned long long)qid.path, qid.version);

    memmove(&fid->qid, &qid, sizeof(struct p9_qid));

    p9_free_req(clnt, req);
    return fid;

error:
    if (fid)
        p9_fid_destroy(fid);
    return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_attach);

struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
        char **wnames, int clone)
{
    int err;
    struct p9_client *clnt;
    struct p9_fid *fid;
    struct p9_qid *wqids;
    struct p9_req_t *req;
    uint16_t nwqids, count;

    err = 0;
    wqids = NULL;
    clnt = oldfid->clnt;
    if (clone) {
        fid = p9_fid_create(clnt);
        if (IS_ERR(fid)) {
            err = PTR_ERR(fid);
            fid = NULL;
            goto error;
        }

        fid->uid = oldfid->uid;
    } else
        fid = oldfid;


    p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
         oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);

    req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
                                nwname, wnames);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    err = p9pdu_readf(req->rc, clnt->proto_version, "R", &nwqids, &wqids);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        p9_free_req(clnt, req);
        goto clunk_fid;
    }
    p9_free_req(clnt, req);

    p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);

    if (nwqids != nwname) {
        err = -ENOENT;
        goto clunk_fid;
    }

    for (count = 0; count < nwqids; count++)
        p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
            count, wqids[count].type,
            (unsigned long long)wqids[count].path,
            wqids[count].version);

    if (nwname)
        memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
    else
        fid->qid = oldfid->qid;

    kfree(wqids);
    return fid;

clunk_fid:
    kfree(wqids);
    p9_client_clunk(fid);
    fid = NULL;

error:
    if (fid && (fid != oldfid))
        p9_fid_destroy(fid);

    return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_walk);

int p9_client_open(struct p9_fid *fid, int mode)
{
    int err;
    struct p9_client *clnt;
    struct p9_req_t *req;
    struct p9_qid qid;
    int iounit;

    clnt = fid->clnt;
    p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
        p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
    err = 0;

    if (fid->mode != -1)
        return -EINVAL;

    if (p9_is_proto_dotl(clnt))
        req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
    else
        req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        goto free_and_error;
    }

    p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
        p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
        (unsigned long long)qid.path, qid.version, iounit);

    fid->mode = mode;
    fid->iounit = iounit;

free_and_error:
    p9_free_req(clnt, req);
error:
    return err;
}
EXPORT_SYMBOL(p9_client_open);

int p9_client_create_dotl(struct p9_fid *ofid, char *name, u32 flags, u32 mode,
        gid_t gid, struct p9_qid *qid)
{
    int err = 0;
    struct p9_client *clnt;
    struct p9_req_t *req;
    int iounit;

    p9_debug(P9_DEBUG_9P,
            ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
            ofid->fid, name, flags, mode, gid);
    clnt = ofid->clnt;

    if (ofid->mode != -1)
        return -EINVAL;

    req = p9_client_rpc(clnt, P9_TLCREATE, "dsddd", ofid->fid, name, flags,
            mode, gid);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", qid, &iounit);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        goto free_and_error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
            qid->type,
            (unsigned long long)qid->path,
            qid->version, iounit);

    ofid->mode = mode;
    ofid->iounit = iounit;

free_and_error:
    p9_free_req(clnt, req);
error:
    return err;
}
EXPORT_SYMBOL(p9_client_create_dotl);

int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
             char *extension)
{
    int err;
    struct p9_client *clnt;
    struct p9_req_t *req;
    struct p9_qid qid;
    int iounit;

    p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
                        fid->fid, name, perm, mode);
    err = 0;
    clnt = fid->clnt;

    if (fid->mode != -1)
        return -EINVAL;

    req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
                mode, extension);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        goto free_and_error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
                qid.type,
                (unsigned long long)qid.path,
                qid.version, iounit);

    fid->mode = mode;
    fid->iounit = iounit;

free_and_error:
    p9_free_req(clnt, req);
error:
    return err;
}
EXPORT_SYMBOL(p9_client_fcreate);

int p9_client_symlink(struct p9_fid *dfid, char *name, char *symtgt, gid_t gid,
        struct p9_qid *qid)
{
    int err = 0;
    struct p9_client *clnt;
    struct p9_req_t *req;

    p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
            dfid->fid, name, symtgt);
    clnt = dfid->clnt;

    req = p9_client_rpc(clnt, P9_TSYMLINK, "dssd", dfid->fid, name, symtgt,
            gid);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        goto free_and_error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
            qid->type, (unsigned long long)qid->path, qid->version);

free_and_error:
    p9_free_req(clnt, req);
error:
    return err;
}
EXPORT_SYMBOL(p9_client_symlink);

int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, char *newname)
{
    struct p9_client *clnt;
    struct p9_req_t *req;

    p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
            dfid->fid, oldfid->fid, newname);
    clnt = dfid->clnt;
    req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
            newname);
    if (IS_ERR(req))
        return PTR_ERR(req);

    p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
    p9_free_req(clnt, req);
    return 0;
}
EXPORT_SYMBOL(p9_client_link);

int p9_client_fsync(struct p9_fid *fid, int datasync)
{
    int err;
    struct p9_client *clnt;
    struct p9_req_t *req;

    p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
            fid->fid, datasync);
    err = 0;
    clnt = fid->clnt;

    req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);

    p9_free_req(clnt, req);

error:
    return err;
}
EXPORT_SYMBOL(p9_client_fsync);

int p9_client_clunk(struct p9_fid *fid)
{
    int err;
    struct p9_client *clnt;
    struct p9_req_t *req;
    int retries = 0;

    if (!fid) {
        pr_warn("%s (%d): Trying to clunk with NULL fid\n",
            __func__, task_pid_nr(current));
        dump_stack();
        return 0;
    }

again:
    p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n", fid->fid,
                                retries);
    err = 0;
    clnt = fid->clnt;

    req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);

    p9_free_req(clnt, req);
error:
    /*
     * Fid is not valid even after a failed clunk
     * If interrupted, retry once then give up and
     * leak fid until umount.
     */
    if (err == -ERESTARTSYS) {
        if (retries++ == 0)
            goto again;
    } else
        p9_fid_destroy(fid);
    return err;
}
EXPORT_SYMBOL(p9_client_clunk);

int p9_client_remove(struct p9_fid *fid)
{
    int err;
    struct p9_client *clnt;
    struct p9_req_t *req;

    p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
    err = 0;
    clnt = fid->clnt;

    req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);

    p9_free_req(clnt, req);
error:
    if (err == -ERESTARTSYS)
        p9_client_clunk(fid);
    else
        p9_fid_destroy(fid);
    return err;
}
EXPORT_SYMBOL(p9_client_remove);

int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
{
    int err = 0;
    struct p9_req_t *req;
    struct p9_client *clnt;

    p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
           dfid->fid, name, flags);

    clnt = dfid->clnt;
    req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }
    p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);

    p9_free_req(clnt, req);
error:
    return err;
}
EXPORT_SYMBOL(p9_client_unlinkat);

int
p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset,
                                u32 count)
{
    char *dataptr;
    int kernel_buf = 0;
    struct p9_req_t *req;
    struct p9_client *clnt;
    int err, rsize, non_zc = 0;


    p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n",
           fid->fid, (unsigned long long) offset, count);
    err = 0;
    clnt = fid->clnt;

    rsize = fid->iounit;
    if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
        rsize = clnt->msize - P9_IOHDRSZ;

    if (count < rsize)
        rsize = count;

    /* Don't bother zerocopy for small IO (< 1024) */
    if (clnt->trans_mod->zc_request && rsize > 1024) {
        char *indata;
        if (data) {
            kernel_buf = 1;
            indata = data;
        } else
            indata = (__force char *)udata;
        /*
         * response header len is 11
         * PDU Header(7) + IO Size (4)
         */
        req = p9_client_zc_rpc(clnt, P9_TREAD, indata, NULL, rsize, 0,
                       11, kernel_buf, "dqd", fid->fid,
                       offset, rsize);
    } else {
        non_zc = 1;
        req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
                    rsize);
    }
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        goto free_and_error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);

    if (non_zc) {
        if (data) {
            memmove(data, dataptr, count);
        } else {
            err = copy_to_user(udata, dataptr, count);
            if (err) {
                err = -EFAULT;
                goto free_and_error;
            }
        }
    }
    p9_free_req(clnt, req);
    return count;

free_and_error:
    p9_free_req(clnt, req);
error:
    return err;
}
EXPORT_SYMBOL(p9_client_read);

int
p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
                            u64 offset, u32 count)
{
    int err, rsize;
    int kernel_buf = 0;
    struct p9_client *clnt;
    struct p9_req_t *req;

    p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %d\n",
                fid->fid, (unsigned long long) offset, count);
    err = 0;
    clnt = fid->clnt;

    rsize = fid->iounit;
    if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
        rsize = clnt->msize - P9_IOHDRSZ;

    if (count < rsize)
        rsize = count;

    /* Don't bother zerocopy for small IO (< 1024) */
    if (clnt->trans_mod->zc_request && rsize > 1024) {
        char *odata;
        if (data) {
            kernel_buf = 1;
            odata = data;
        } else
            odata = (char *)udata;
        req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, odata, 0, rsize,
                       P9_ZC_HDR_SZ, kernel_buf, "dqd",
                       fid->fid, offset, rsize);
    } else {
        if (data)
            req = p9_client_rpc(clnt, P9_TWRITE, "dqD", fid->fid,
                        offset, rsize, data);
        else
            req = p9_client_rpc(clnt, P9_TWRITE, "dqU", fid->fid,
                        offset, rsize, udata);
    }
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    err = p9pdu_readf(req->rc, clnt->proto_version, "d", &count);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        goto free_and_error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);

    p9_free_req(clnt, req);
    return count;

free_and_error:
    p9_free_req(clnt, req);
error:
    return err;
}
EXPORT_SYMBOL(p9_client_write);

struct p9_wstat *p9_client_stat(struct p9_fid *fid)
{
    int err;
    struct p9_client *clnt;
    struct p9_wstat *ret = kmalloc(sizeof(struct p9_wstat), GFP_KERNEL);
    struct p9_req_t *req;
    u16 ignored;

    p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);

    if (!ret)
        return ERR_PTR(-ENOMEM);

    err = 0;
    clnt = fid->clnt;

    req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    err = p9pdu_readf(req->rc, clnt->proto_version, "wS", &ignored, ret);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        p9_free_req(clnt, req);
        goto error;
    }

    p9_debug(P9_DEBUG_9P,
        "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
        "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
        "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
        "<<<    uid=%d gid=%d n_muid=%d\n",
        ret->size, ret->type, ret->dev, ret->qid.type,
        (unsigned long long)ret->qid.path, ret->qid.version, ret->mode,
        ret->atime, ret->mtime, (unsigned long long)ret->length,
        ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
        ret->n_uid, ret->n_gid, ret->n_muid);

    p9_free_req(clnt, req);
    return ret;

error:
    kfree(ret);
    return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_stat);

struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
                            u64 request_mask)
{
    int err;
    struct p9_client *clnt;
    struct p9_stat_dotl *ret = kmalloc(sizeof(struct p9_stat_dotl),
                                GFP_KERNEL);
    struct p9_req_t *req;

    p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
                            fid->fid, request_mask);

    if (!ret)
        return ERR_PTR(-ENOMEM);

    err = 0;
    clnt = fid->clnt;

    req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    err = p9pdu_readf(req->rc, clnt->proto_version, "A", ret);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        p9_free_req(clnt, req);
        goto error;
    }

    p9_debug(P9_DEBUG_9P,
        "<<< RGETATTR st_result_mask=%lld\n"
        "<<< qid=%x.%llx.%x\n"
        "<<< st_mode=%8.8x st_nlink=%llu\n"
        "<<< st_uid=%d st_gid=%d\n"
        "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
        "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
        "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
        "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
        "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
        "<<< st_gen=%lld st_data_version=%lld",
        ret->st_result_mask, ret->qid.type, ret->qid.path,
        ret->qid.version, ret->st_mode, ret->st_nlink, ret->st_uid,
        ret->st_gid, ret->st_rdev, ret->st_size, ret->st_blksize,
        ret->st_blocks, ret->st_atime_sec, ret->st_atime_nsec,
        ret->st_mtime_sec, ret->st_mtime_nsec, ret->st_ctime_sec,
        ret->st_ctime_nsec, ret->st_btime_sec, ret->st_btime_nsec,
        ret->st_gen, ret->st_data_version);

    p9_free_req(clnt, req);
    return ret;

error:
    kfree(ret);
    return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_getattr_dotl);

static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
{
    int ret;

    /* NOTE: size shouldn't include its own length */
    /* size[2] type[2] dev[4] qid[13] */
    /* mode[4] atime[4] mtime[4] length[8]*/
    /* name[s] uid[s] gid[s] muid[s] */
    ret = 2+4+13+4+4+4+8+2+2+2+2;

    if (wst->name)
        ret += strlen(wst->name);
    if (wst->uid)
        ret += strlen(wst->uid);
    if (wst->gid)
        ret += strlen(wst->gid);
    if (wst->muid)
        ret += strlen(wst->muid);

    if ((proto_version == p9_proto_2000u) ||
        (proto_version == p9_proto_2000L)) {
        ret += 2+4+4+4; /* extension[s] n_uid[4] n_gid[4] n_muid[4] */
        if (wst->extension)
            ret += strlen(wst->extension);
    }

    return ret;
}

int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
{
    int err;
    struct p9_req_t *req;
    struct p9_client *clnt;

    err = 0;
    clnt = fid->clnt;
    wst->size = p9_client_statsize(wst, clnt->proto_version);
    p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
    p9_debug(P9_DEBUG_9P,
        "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
        "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
        "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
        "     uid=%d gid=%d n_muid=%d\n",
        wst->size, wst->type, wst->dev, wst->qid.type,
        (unsigned long long)wst->qid.path, wst->qid.version, wst->mode,
        wst->atime, wst->mtime, (unsigned long long)wst->length,
        wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
        wst->n_uid, wst->n_gid, wst->n_muid);

    req = p9_client_rpc(clnt, P9_TWSTAT, "dwS", fid->fid, wst->size+2, wst);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);

    p9_free_req(clnt, req);
error:
    return err;
}
EXPORT_SYMBOL(p9_client_wstat);

int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
{
    int err;
    struct p9_req_t *req;
    struct p9_client *clnt;

    err = 0;
    clnt = fid->clnt;
    p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
    p9_debug(P9_DEBUG_9P,
        "    valid=%x mode=%x uid=%d gid=%d size=%lld\n"
        "    atime_sec=%lld atime_nsec=%lld\n"
        "    mtime_sec=%lld mtime_nsec=%lld\n",
        p9attr->valid, p9attr->mode, p9attr->uid, p9attr->gid,
        p9attr->size, p9attr->atime_sec, p9attr->atime_nsec,
        p9attr->mtime_sec, p9attr->mtime_nsec);

    req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);

    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }
    p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
    p9_free_req(clnt, req);
error:
    return err;
}
EXPORT_SYMBOL(p9_client_setattr);

int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
{
    int err;
    struct p9_req_t *req;
    struct p9_client *clnt;

    err = 0;
    clnt = fid->clnt;

    p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);

    req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    err = p9pdu_readf(req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
        &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
        &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        p9_free_req(clnt, req);
        goto error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RSTATFS fid %d type 0x%lx bsize %ld "
        "blocks %llu bfree %llu bavail %llu files %llu ffree %llu "
        "fsid %llu namelen %ld\n",
        fid->fid, (long unsigned int)sb->type, (long int)sb->bsize,
        sb->blocks, sb->bfree, sb->bavail, sb->files,  sb->ffree,
        sb->fsid, (long int)sb->namelen);

    p9_free_req(clnt, req);
error:
    return err;
}
EXPORT_SYMBOL(p9_client_statfs);

int p9_client_rename(struct p9_fid *fid,
             struct p9_fid *newdirfid, const char *name)
{
    int err;
    struct p9_req_t *req;
    struct p9_client *clnt;

    err = 0;
    clnt = fid->clnt;

    p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
            fid->fid, newdirfid->fid, name);

    req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
            newdirfid->fid, name);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);

    p9_free_req(clnt, req);
error:
    return err;
}
EXPORT_SYMBOL(p9_client_rename);

int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
               struct p9_fid *newdirfid, const char *new_name)
{
    int err;
    struct p9_req_t *req;
    struct p9_client *clnt;

    err = 0;
    clnt = olddirfid->clnt;

    p9_debug(P9_DEBUG_9P, ">>> TRENAMEAT olddirfid %d old name %s"
           " newdirfid %d new name %s\n", olddirfid->fid, old_name,
           newdirfid->fid, new_name);

    req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
                old_name, newdirfid->fid, new_name);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
           newdirfid->fid, new_name);

    p9_free_req(clnt, req);
error:
    return err;
}
EXPORT_SYMBOL(p9_client_renameat);

/*
 * An xattrwalk without @attr_name gives the fid for the lisxattr namespace
 */
struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
                const char *attr_name, u64 *attr_size)
{
    int err;
    struct p9_req_t *req;
    struct p9_client *clnt;
    struct p9_fid *attr_fid;

    err = 0;
    clnt = file_fid->clnt;
    attr_fid = p9_fid_create(clnt);
    if (IS_ERR(attr_fid)) {
        err = PTR_ERR(attr_fid);
        attr_fid = NULL;
        goto error;
    }
    p9_debug(P9_DEBUG_9P,
        ">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
        file_fid->fid, attr_fid->fid, attr_name);

    req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
            file_fid->fid, attr_fid->fid, attr_name);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }
    err = p9pdu_readf(req->rc, clnt->proto_version, "q", attr_size);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        p9_free_req(clnt, req);
        goto clunk_fid;
    }
    p9_free_req(clnt, req);
    p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
        attr_fid->fid, *attr_size);
    return attr_fid;
clunk_fid:
    p9_client_clunk(attr_fid);
    attr_fid = NULL;
error:
    if (attr_fid && (attr_fid != file_fid))
        p9_fid_destroy(attr_fid);

    return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(p9_client_xattrwalk);

int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
            u64 attr_size, int flags)
{
    int err;
    struct p9_req_t *req;
    struct p9_client *clnt;

    p9_debug(P9_DEBUG_9P,
        ">>> TXATTRCREATE fid %d name  %s size %lld flag %d\n",
        fid->fid, name, (long long)attr_size, flags);
    err = 0;
    clnt = fid->clnt;
    req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
            fid->fid, name, attr_size, flags);
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }
    p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
    p9_free_req(clnt, req);
error:
    return err;
}
EXPORT_SYMBOL_GPL(p9_client_xattrcreate);

int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
{
    int err, rsize, non_zc = 0;
    struct p9_client *clnt;
    struct p9_req_t *req;
    char *dataptr;

    p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
                fid->fid, (unsigned long long) offset, count);

    err = 0;
    clnt = fid->clnt;

    rsize = fid->iounit;
    if (!rsize || rsize > clnt->msize-P9_READDIRHDRSZ)
        rsize = clnt->msize - P9_READDIRHDRSZ;

    if (count < rsize)
        rsize = count;

    /* Don't bother zerocopy for small IO (< 1024) */
    if (clnt->trans_mod->zc_request && rsize > 1024) {
        /*
         * response header len is 11
         * PDU Header(7) + IO Size (4)
         */
        req = p9_client_zc_rpc(clnt, P9_TREADDIR, data, NULL, rsize, 0,
                       11, 1, "dqd", fid->fid, offset, rsize);
    } else {
        non_zc = 1;
        req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
                    offset, rsize);
    }
    if (IS_ERR(req)) {
        err = PTR_ERR(req);
        goto error;
    }

    err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        goto free_and_error;
    }

    p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);

    if (non_zc)
        memmove(data, dataptr, count);

    p9_free_req(clnt, req);
    return count;

free_and_error:
    p9_free_req(clnt, req);
error:
    return err;
}
EXPORT_SYMBOL(p9_client_readdir);

int p9_client_mknod_dotl(struct p9_fid *fid, char *name, int mode,
            dev_t rdev, gid_t gid, struct p9_qid *qid)
{
    int err;
    struct p9_client *clnt;
    struct p9_req_t *req;

    err = 0;
    clnt = fid->clnt;
    p9_debug(P9_DEBUG_9P, ">>> TMKNOD fid %d name %s mode %d major %d "
        "minor %d\n", fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
    req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddd", fid->fid, name, mode,
        MAJOR(rdev), MINOR(rdev), gid);
    if (IS_ERR(req))
        return PTR_ERR(req);

    err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        goto error;
    }
    p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n", qid->type,
                (unsigned long long)qid->path, qid->version);

error:
    p9_free_req(clnt, req);
    return err;

}
EXPORT_SYMBOL(p9_client_mknod_dotl);

int p9_client_mkdir_dotl(struct p9_fid *fid, char *name, int mode,
                gid_t gid, struct p9_qid *qid)
{
    int err;
    struct p9_client *clnt;
    struct p9_req_t *req;

    err = 0;
    clnt = fid->clnt;
    p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
         fid->fid, name, mode, gid);
    req = p9_client_rpc(clnt, P9_TMKDIR, "dsdd", fid->fid, name, mode,
        gid);
    if (IS_ERR(req))
        return PTR_ERR(req);

    err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        goto error;
    }
    p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
                (unsigned long long)qid->path, qid->version);

error:
    p9_free_req(clnt, req);
    return err;

}
EXPORT_SYMBOL(p9_client_mkdir_dotl);

int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
{
    int err;
    struct p9_client *clnt;
    struct p9_req_t *req;

    err = 0;
    clnt = fid->clnt;
    p9_debug(P9_DEBUG_9P, ">>> TLOCK fid %d type %i flags %d "
            "start %lld length %lld proc_id %d client_id %s\n",
            fid->fid, flock->type, flock->flags, flock->start,
            flock->length, flock->proc_id, flock->client_id);

    req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
                flock->flags, flock->start, flock->length,
                    flock->proc_id, flock->client_id);

    if (IS_ERR(req))
        return PTR_ERR(req);

    err = p9pdu_readf(req->rc, clnt->proto_version, "b", status);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        goto error;
    }
    p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
error:
    p9_free_req(clnt, req);
    return err;

}
EXPORT_SYMBOL(p9_client_lock_dotl);

int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
{
    int err;
    struct p9_client *clnt;
    struct p9_req_t *req;

    err = 0;
    clnt = fid->clnt;
    p9_debug(P9_DEBUG_9P, ">>> TGETLOCK fid %d, type %i start %lld "
        "length %lld proc_id %d client_id %s\n", fid->fid, glock->type,
        glock->start, glock->length, glock->proc_id, glock->client_id);

    req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,  glock->type,
        glock->start, glock->length, glock->proc_id, glock->client_id);

    if (IS_ERR(req))
        return PTR_ERR(req);

    err = p9pdu_readf(req->rc, clnt->proto_version, "bqqds", &glock->type,
            &glock->start, &glock->length, &glock->proc_id,
            &glock->client_id);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        goto error;
    }
    p9_debug(P9_DEBUG_9P, "<<< RGETLOCK type %i start %lld length %lld "
        "proc_id %d client_id %s\n", glock->type, glock->start,
        glock->length, glock->proc_id, glock->client_id);
error:
    p9_free_req(clnt, req);
    return err;
}
EXPORT_SYMBOL(p9_client_getlock_dotl);

int p9_client_readlink(struct p9_fid *fid, char **target)
{
    int err;
    struct p9_client *clnt;
    struct p9_req_t *req;

    err = 0;
    clnt = fid->clnt;
    p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);

    req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
    if (IS_ERR(req))
        return PTR_ERR(req);

    err = p9pdu_readf(req->rc, clnt->proto_version, "s", target);
    if (err) {
        trace_9p_protocol_dump(clnt, req->rc);
        goto error;
    }
    p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
error:
    p9_free_req(clnt, req);
    return err;
}
EXPORT_SYMBOL(p9_client_readlink);